Changes In Anti-Nutritional Factors, Bioactive And Rheological Properties Of Milk Made From Germinated Green Kernel Black Gram (Vigna Cylindrica (L.) Skeels)

Abstract

The main purpose of research was to determine the influences of germination time (0, 12, 24, 36 and 48 h) on the bioactive compounds, anti-nutrient factors like tannin and phytates and viscosity properties of raw and cooked black gram milk. Bioactive compounds, including phenolics and anthocyanins reduced significantly in their contents after 48-hour germination. As a result, the antioxidant capacity of germinated black gram milk which was measured by DPPH scavenging activity also decreased with germination time. Furthermore, after 48 hour of germination, tannin was recorded to reduce significantly from 108.6 to 43.0 mg/100 g dry solid for the uncooked samples and from 99.4 to 37.2 mg/100 g dry solid for the cooked samples. Regarding to phytates, germination caused a slight decrease in content, while with the combination of high temperature during cooking process, phytates content showed a remarkable reduction from 1068 to 868 mg/100 g dry solid. In addition, germination also showed positive effects on fiber and gamma-aminobutyric acid (GABA) contents. GABA received the highest value after 24 hours of germination, at around 98.6 µg/100 g dry solid, while the highest value in dietary fiber was reported at 48 hours of germination. Regarding to rheological properties, viscosity of milk decreased significantly with an increase in germination time, from 7.45 mPas to 2.22 mPas. In sensory evaluation test, even though the 24 h germinated black gram milk got lower scores than the control sample, its scores indicated a certain acceptability of consumers. In conclusion, although germination process caused a significantly reduction in antioxidant properties, it also helped to decrease the level of anti-nutrients, improve the quality of black gram milk by enhancing GABA and dietary fiber levels.